The fly-in, fly-out worker was pulled from the water by fellow surfers and received CPR on the beach before being taken to hospital.

He died in Royal Perth Hospital Friday night from his injuries.

Witnesses at the scene on Tuesday said Mr Gerring's leg was severed above the knee.

The WA Department of Fisheries (DoF) has said the damage to his surfboard indicated he was attacked by a great white shark.

Mr Gerring is the 13th person to die from a shark attack in WA since 2000.

Fatal shark attacks in WA since 2000

Spearfisher Jay Muscat: Cheynes Beach December 29, 2014

Surfer Chris Boyd: Gracetown November 23, 2013

Surfer Ben Linden: Wedge Island, July 14, 2012

Diver Peter Kurmann: Geographe Bay, March 31, 2012

Diver George Wainwright: Rottnest Island, Oct 22, 2011

Swimmer Bryn Martin: Cottesloe Beach, Oct 10, 2011

Surfer Kyle Burden: Bunker Bay, Sept 4, 2011

Surfer Nick Edwards: Gracetown, Aug 17, 2010

Snorkeller Brian Guest: Port Kennedy, Dec 27, 2008

Snorkeller Geoffrey Brazier: Abrolhos Islands, Mar 19, 2005

Surfer Brad Smith: Gracetown, July 10, 2004

Swimmer Ken Crew: North Cottesloe, Nov 6, 2000

Mr Gerring's brother Rick thanked the "heroes" that brought his injured brother back to shore and the medical staff who cared for him throughout the "traumatic ordeal".

"The hospital staff gave us those [three] days [with Ben]. Obviously we were always hoping for the best outcome, it was always at the back of our minds that this could happen, but they gave us that time to say our goodbyes," he told ABC News.

Rick Gerring said his brother was a naturally gifted sportsman, whether it was track and field, skateboarding, snowboarding or surfing.

"Ben loved the ocean, crabbing and surfing but his greatest love is and always will be Jasmine; he was so proud to become a father and a husband," he said.

Mr Gerring's fiancee Jasmine Boyer is pregnant with their first child.

"That is the hardest part and I can't even imagine what Jasmine is feeling right now, but … we will always support Jasmine and my nephew or niece. We will do everything to be there," Rick Gerring said.

A 4.2-metre shark was caught on Wednesday afternoon on a baited drum line set up near where Mr Gerring was attacked.

However the Department of Fisheries (DoF) said it was not possible to tell if that shark — which was not tagged — was responsible for the attack.

Attack sparks fresh shark debate

The DoF has defended shark warnings issued on the day of the attack.

The sighting of a 3.5-metre shark off Pyramids Beach, about five kilometres south of the attack, had been reported earlier in the day, but the DoF said no action was required as it was 1.8 kilometres off the coast.